Pharmacological Investigation of <i>Syzygium diospyrifolium</i> Fruit Extract: Antimicrobial and Diuretic Evidence From Experimental, DFT and Molecular Docking Studies

Syzygium diospyrifolium , a member of the family Myrtaceae, is traditionally used in South and Southeast Asia for the management of infectious and systemic disorders; however, its pharmacological validation remains limited. This study evaluated the antimicrobial and diuretic activities of the methanolic extract of S . diospyrifolium (MESD) fruits using in vitro, in vivo and in silico approaches to substantiate its ethnomedicinal relevance. Antibacterial activity was assessed by the disc diffusion method against selected Gram‐positive and Gram‐negative bacterial strains, while diuretic activity was examined in albino mice by measuring urine volume, electrolyte (Na + , K + and Cl − ) excretion, diuretic index and Lipschitz values, with furosemide serving as the standard reference drug. MESD demonstrated notable antibacterial activity against both bacterial groups, with pronounced inhibition against Pseudomonas aeruginosa and Bacillus megaterium , showing activity comparable to or exceeding that of amoxicillin at the tested concentration. In vivo evaluation revealed a significant, dose‐dependent diuretic effect, characterised by increased urine output and enhanced electrolyte excretion, particularly at a dose of 400 mg/kg, which produced a diuretic index close to that of furosemide. To explore possible mechanisms of action, identified phytoconstituents were subjected to molecular docking against antibacterial (1HTB and 1LX6) and diuretic‐related (1Z9Y and 7S1Y) protein targets using PyRx and CB‐Dock. Friedelan‐3‐one and β‐sitosterol exhibited strong binding affinities comparable to or greater than those of standard drugs. Additionally, ADME/T, toxicity prediction, PASS analysis, density functional theory (DFT) and molecular electrostatic potential studies supported the favourable pharmacokinetic profiles, chemical reactivity and interaction potential of the major compounds. Overall, the findings highlight S. diospyrifolium as a promising natural source of antimicrobial and diuretic agents, warranting further investigation.